Voice/data hybrid mode

ABSTRACT

A method for voice/data hybrid mode within a user equipment (UE). The method includes detecting a first radio access technology (RAT) activity in response to a received first RAT suspend request for a second RAT tune-away. The method also includes adaptively performing the first RAT suspend request according to a predetermined priority of the detected first RAT activity and a second RAT tune-away activity. A receive chain is shared between a first RAT modem and a second RAT modem of the UE.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a divisional of U.S. patent application Ser.No. 13/756,133, filed on Jan. 31, 2013, in the names of A. Swaminathanet al., which claims the benefit of U.S. Provisional Patent ApplicationNo. 61/594,998 filed on Feb. 3, 2012, in the names of A. Swaminathan etal., the disclosures of which are expressly incorporated by referenceherein in their entireties.

BACKGROUND

1. Field

Aspects of the present disclosure relate generally to wirelesscommunication systems, and more particularly to voice/data hybrid modewithin a user equipment (UE).

2. Background

Wireless communication systems are widely deployed to provide varioustelecommunication services such as telephony, video, data, messaging,and broadcasts. Typical wireless communication systems may employmultiple-access technologies capable of supporting communication withmultiple users by sharing available system resources (e.g., bandwidth,transmit power). Examples of such multiple-access technologies includecode division multiple access (CDMA) systems, time division multipleaccess (TDMA) systems, frequency division multiple access (FDMA)systems, orthogonal frequency division multiple access (OFDMA) systems,single-carrier frequency divisional multiple access (SC-FDMA) systems,and time division synchronous code division multiple access (TD-SCDMA)systems.

These multiple access technologies are adopted in varioustelecommunication standards to provide a common protocol that enablesdifferent wireless devices to communicate on a municipal, national,regional, and even global level. An example of an emergingtelecommunication standard is Long Term Evolution (LTE). LTE is a set ofenhancements to the Universal Mobile Telecommunications System (UMTS)mobile standard promulgated by Third Generation Partnership Project(3GPP).

LTE technology is designed to better support mobile broadband Internetaccess by improving spectral efficiency, lower costs, improve services,make use of new spectrum, and better integrate with other open standardsusing OFDMA on the downlink (DL), SC-FDMA on the uplink (UL), andmultiple-input multiple-output (MIMO) antenna technology. As the demandfor mobile broadband access continues to increase, however, there existsa need for further improvements in LTE technology. Preferably, theseimprovements should be applicable to other multi-access technologies andthe telecommunication standards that employ these technologies. Researchand development continue to advance LTE technology not only to meet thegrowing demand for mobile broadband access, but to advance and enhancethe user experience with mobile communications.

SUMMARY

According to one aspect of the present disclosure, a method for avoice/data hybrid mode within a user equipment (UE) is described. Themethod includes detecting a first radio access technology (RAT) activityin response to a received first RAT suspend request for a second RATtune-away. The method also includes adaptively performing the first RATsuspend request according to a predetermined priority of the detectedfirst RAT activity and a second RAT tune-away activity. A receive chainis shared between a first RAT modem and a second RAT modem of the UE.

In another aspect, an apparatus for a voice/data hybrid mode within a UEis described. The apparatus includes at least one processor; and amemory coupled to the at least one processor. The processor(s) isconfigured to detect a first radio access technology (RAT) activity inresponse to a received first RAT suspend request for a second RATtune-away. The processor(s) is also configured to adaptively perform thefirst RAT suspend request according to a predetermined priority of thedetected first RAT activity and a second RAT tune-away activity. Areceive chain is shared between a first RAT modem and a second RAT modemof the UE.

In a further aspect, a computer program product for a voice/data hybridmode within a UE is described. The computer program product includes anon-transitory computer-readable medium having program code recordedthereon. The computer program product has program code to detect a firstradio access technology (RAT) activity in response to a received firstRAT suspend request for a second RAT tune-away. The computer programproduct also has program code to adaptively perform the first RATsuspend request according to a predetermined priority of the detectedfirst RAT activity and a second RAT tune-away activity. A receive chainis shared between a first RAT modem and a second RAT modem of the UE.

In another aspect, an apparatus for a voice/data hybrid mode within a UEis described. The apparatus includes means for detecting a first radioaccess technology (RAT) activity in response to a received first RATsuspend request for a second RAT tune-away. The apparatus furtherincludes means for adaptively performing the first RAT suspend requestaccording to a predetermined priority of the detected first RAT activityand a second RAT tune-away activity. A receive chain is shared between afirst RAT modem and a second RAT modem of the UE.

According to a further aspect of the present disclosure, a method for avoice/data hybrid mode within a UE is described. The method includesadaptively performing a first radio access technology (RAT) scan betweena second radio access technology (RAT) activity in response to an out ofservice (OoS) event. A receive chain is shared between a first RAT modemand a second RAT modem of the UE.

In another aspect, an apparatus for a voice/data hybrid mode within a UEis described. The apparatus includes at least one processor; and amemory coupled to the at least one processor. The processor(s) isconfigured to adaptively perform a first radio access technology (RAT)scan between a second radio access technology (RAT) activity in responseto an out of service (OoS) event. A receive chain is shared between afirst RAT modem and a second RAT modem of the UE.

In a further aspect, a computer program product for 1×/LTE dual domaincamping with a single radio UE is described. The computer programproduct includes a non-transitory computer-readable medium havingprogram code recorded thereon. The computer program product has programcode to adaptively perform a first radio access technology (RAT) scanbetween a second radio access technology (RAT) activity in response toan out of service (OoS) event. A receive chain is shared between a firstRAT modem and a second RAT modem of the UE.

In another aspect, an apparatus for 1×/LTE dual domain camping with asingle radio UE is described. The apparatus includes means foradaptively performing a first radio access technology (RAT) scan betweena second radio access technology (RAT) activity in response to an out ofservice (OoS) event. A receive chain is shared between a first RAT modemand a second RAT modem of the UE.

This has outlined, rather broadly, the features and technical advantagesof the present disclosure in order that the detailed description thatfollows may be better understood. Additional features and advantages ofthe disclosure will be described below. It should be appreciated bythose skilled in the art that this disclosure may be readily utilized asa basis for modifying or designing other structures for carrying out thesame purposes of the present disclosure. It should also be realized bythose skilled in the art that such equivalent constructions do notdepart from the teachings of the disclosure as set forth in the appendedclaims. The novel features, which are believed to be characteristic ofthe disclosure, both as to its organization and method of operation,together with further objects and advantages, will be better understoodfrom the following description when considered in connection with theaccompanying figures. It is to be expressly understood, however, thateach of the figures is provided for the purpose of illustration anddescription only and is not intended as a definition of the limits ofthe present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The features, nature, and advantages of the present disclosure willbecome more apparent from the detailed description set forth below whentaken in conjunction with the drawings in which like referencecharacters identify correspondingly throughout.

FIG. 1 is a diagram illustrating an example of a network architecture.

FIG. 2 is a diagram illustrating an example of an access network.

FIG. 3 is a diagram illustrating an example of a downlink framestructure in LTE.

FIG. 4 is a diagram illustrating an example of an uplink frame structurein LTE.

FIG. 5 is a diagram illustrating an example of a radio protocolarchitecture for the user and control plane.

FIG. 6 is a diagram illustrating an example of an evolved Node B anduser equipment in an access network.

FIG. 7 is a block diagram illustrating a method for a voice/data hybridmode within a UE according to an aspect of the present disclosure.

FIG. 8 is a block diagram illustrating a method for a voice/data hybridmode within a UE using adaptive scanning according to an aspect of thepresent disclosure.

FIG. 9 is a diagram illustrating an example of a hardware implementationfor an apparatus employing a UE with a voice/data hybrid mode systemaccording to one aspect of the present disclosure.

DETAILED DESCRIPTION

The detailed description set forth below, in connection with theappended drawings, is intended as a description of variousconfigurations and is not intended to represent the only configurationsin which the concepts described herein may be practiced. The detaileddescription includes specific details for the purpose of providing athorough understanding of the various concepts. However, it will beapparent to those skilled in the art that these concepts may bepracticed without these specific details. In some instances, well-knownstructures and components are shown in block diagram form in order toavoid obscuring such concepts.

Aspects of the telecommunication systems are presented with reference tovarious apparatus and methods. These apparatus and methods are describedin the following detailed description and illustrated in theaccompanying drawings by various blocks, modules, components, circuits,steps, processes, algorithms, etc. (collectively referred to as“elements”). These elements may be implemented using electronichardware, computer software, or any combination thereof. Whether suchelements are implemented as hardware or software depends upon theparticular application and design constraints imposed on the overallsystem.

By way of example, an element, or any portion of an element, or anycombination of elements may be implemented with a “processing system”that includes one or more processors. Examples of processors includemicroprocessors, microcontrollers, digital signal processors (DSPs),field programmable gate arrays (FPGAs), programmable logic devices(PLDs), state machines, gated logic, discrete hardware circuits, andother suitable hardware configured to perform the various functionalitydescribed throughout this disclosure. One or more processors in theprocessing system may execute software. Software shall be construedbroadly to mean instructions, instruction sets, code, code segments,program code, programs, subprograms, software modules, applications,software applications, software packages, routines, subroutines,objects, executables, threads of execution, procedures, functions, etc.,whether referred to as software, firmware, middleware, microcode,hardware description language, or otherwise.

Accordingly, in one or more exemplary embodiments, the functionsdescribed may be implemented in hardware, software, firmware, or anycombination thereof. If implemented in software, the functions may bestored on or encoded as one or more instructions or code on acomputer-readable medium. Computer-readable media includes computerstorage media. Storage media may be any available media that can beaccessed by a computer. By way of example, and not limitation, suchcomputer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or otheroptical disk storage, magnetic disk storage or other magnetic storagedevices, or any other medium that can be used to carry or store desiredprogram code in the form of instructions or data structures and that canbe accessed by a computer. Disk and disc, as used herein, includescompact disc (CD), laser disc, optical disc, digital versatile disc(DVD), floppy disk and Blu-ray disc where disks usually reproduce datamagnetically, while discs reproduce data optically with lasers.Combinations of the above should also be included within the scope ofcomputer-readable media.

FIG. 1 is a diagram illustrating an LTE network architecture 100, whichmay be an LTE/-A network, in which a voice/data hybrid mode with a UEmay be performed, according to one aspect of the present disclosure. TheLTE network architecture 100 may be referred to as an Evolved PacketSystem (EPS) 100. The EPS 100 may include one or more user equipment(UE) 102, an Evolved UMTS Terrestrial Radio Access Network (E-UTRAN)104, an Evolved Packet Core (EPC) 110, a Home Subscriber Server (HSS)120, and an Operator's IP Services 122. The EPS can interconnect withother access networks, but for simplicity those entities/interfaces arenot shown. As shown, the EPS provides packet-switched services, however,as those skilled in the art will readily appreciate, the variousconcepts presented throughout this disclosure may be extended tonetworks providing circuit-switched services.

The E-UTRAN includes the evolved Node B (eNodeB) 106 and other eNodeBs108. The eNodeB 106 provides user and control plane protocolterminations toward the UE 102. The eNodeB 106 may be connected to theother eNodeBs 108 via a backhaul (e.g., an X2 interface). The eNodeB 106may also be referred to as a base station, a base transceiver station, aradio base station, a radio transceiver, a transceiver function, a basicservice set (BSS), an extended service set (ESS), or some other suitableterminology. The eNodeB 106 provides an access point to the EPC 110 fora UE 102. Examples of UEs 102 include a cellular phone, a smart phone, asession initiation protocol (SIP) phone, a laptop, a personal digitalassistant (PDA), a satellite radio, a global positioning system, amultimedia device, a video device, a digital audio player (e.g., MP3player), a camera, a game console, or any other similar functioningdevice. The UE 102 may also be referred to by those skilled in the artas a mobile station, a subscriber station, a mobile unit, a subscriberunit, a wireless unit, a remote unit, a mobile device, a wirelessdevice, a wireless communications device, a remote device, a mobilesubscriber station, an access terminal, a mobile terminal, a wirelessterminal, a remote terminal, a handset, a user agent, a mobile client, aclient, or some other suitable terminology.

The eNodeB 106 is connected to the EPC 110 via, e.g., an 51 interface.The EPC 110 includes a Mobility Management Entity (MME) 112, other MMEs114, a Serving Gateway 116, and a Packet Data Network (PDN) Gateway 118.The MME 112 is the control node that processes the signaling between theUE 102 and the EPC 110. Generally, the MME 112 provides bearer andconnection management. All user IP packets are transferred through theServing Gateway 116, which itself is connected to the PDN Gateway 118.The PDN Gateway 118 provides UE IP address allocation as well as otherfunctions. The PDN Gateway 118 is connected to the Operator's IPServices 122. The Operator's IP Services 122 may include the Internet,the Intranet, an IP Multimedia Subsystem (IMS), and a PS StreamingService (PSS).

FIG. 2 is a diagram illustrating an example of an access network 200 inan LTE network architecture. In this example, the access network 200 isdivided into a number of cellular regions (cells) 202. One or more lowerpower class eNodeBs 208 may have cellular regions 210 that overlap withone or more of the cells 202. The lower power class eNodeB 208 may be aremote radio head (RRH), a femto cell (e.g., home eNodeB (HeNodeB)),pico cell, or micro cell. The macro eNodeBs 204 are each assigned to arespective cell 202 and are configured to provide an access point to theEPC 110 for all the UEs 206 in the cells 202. There is no centralizedcontroller in this example of an access network 200, but a centralizedcontroller may be used in alternative configurations. The eNodeBs 204are responsible for all radio related functions including radio bearercontrol, admission control, mobility control, scheduling, security, andconnectivity to the serving gateway 116.

The modulation and multiple access scheme employed by the access network200 may vary depending on the particular telecommunications standardbeing deployed. In LTE applications, OFDM is used on the downlink andSC-FDMA is used on the uplink to support both frequency divisionduplexing (FDD) and time division duplexing (TDD). As those skilled inthe art will readily appreciate from the detailed description to follow,the various concepts presented herein are well suited for LTEapplications. However, these concepts may be readily extended to othertelecommunication standards employing other modulation and multipleaccess techniques. By way of example, these concepts may be extended toEvolution-Data Optimized (EV-DO) or Ultra Mobile Broadband (UMB). EV-DOand UMB are air interface standards promulgated by the 3rd GenerationPartnership Project 2 (3GPP2) as part of the CDMA2000 family ofstandards and employs CDMA to provide broadband Internet access tomobile stations. These concepts may also be extended to UniversalTerrestrial Radio Access (UTRA) employing Wideband-CDMA (W-CDMA) andother variants of CDMA, such as TD-SCDMA; Global System for MobileCommunications (GSM) employing TDMA; and Evolved UTRA (E-UTRA), UltraMobile Broadband (UMB), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE802.20, and Flash-OFDM employing OFDMA. UTRA, E-UTRA, UMTS, LTE and GSMare described in documents from the 3GPP organization. CDMA2000 and UMBare described in documents from the 3GPP2 organization. The actualwireless communication standard and the multiple access technologyemployed will depend on the specific application and the overall designconstraints imposed on the system.

The eNodeBs 204 may have multiple antennas supporting MIMO technology.The use of MIMO technology enables the eNodeBs 204 to exploit thespatial domain to support spatial multiplexing, beamforming, andtransmit diversity. Spatial multiplexing may be used to transmitdifferent streams of data simultaneously on the same frequency. The datasteams may be transmitted to a single UE 206 to increase the data rateor to multiple UEs 206 to increase the overall system capacity. This isachieved by spatially precoding each data stream (i.e., applying ascaling of an amplitude and a phase) and then transmitting eachspatially precoded stream through multiple transmit antennas on thedownlink. The spatially precoded data streams arrive at the UE(s) 206with different spatial signatures, which enables each of the UE(s) 206to recover the one or more data streams destined for that UE 206. On theuplink, each UE 206 transmits a spatially precoded data stream, whichenables the eNodeB 204 to identify the source of each spatially precodeddata stream.

Spatial multiplexing is generally used when channel conditions are good.When channel conditions are less favorable, beamforming may be used tofocus the transmission energy in one or more directions. This may beachieved by spatially precoding the data for transmission throughmultiple antennas. To achieve good coverage at the edges of the cell, asingle stream beamforming transmission may be used in combination withtransmit diversity.

In the detailed description that follows, various aspects of an accessnetwork will be described with reference to a MIMO system supportingOFDM on the downlink. OFDM is a spread-spectrum technique that modulatesdata over a number of subcarriers within an OFDM symbol. The subcarriersare spaced apart at precise frequencies. The spacing provides“orthogonality” that enables a receiver to recover the data from thesubcarriers. In the time domain, a guard interval (e.g., cyclic prefix)may be added to each OFDM symbol to combat inter-OFDM-symbolinterference. The uplink may use SC-FDMA in the form of a DFT-spreadOFDM signal to compensate for high peak-to-average power ratio (PAPR).

FIG. 3 is a diagram 300 illustrating an example of a downlink framestructure in LTE. A frame (10 ms) may be divided into 10 equally sizedsub-frames. Each sub-frame may include two consecutive time slots. Aresource grid may be used to represent two time slots, each time slotincluding a resource block. The resource grid is divided into multipleresource elements. In LTE, a resource block contains 12 consecutivesubcarriers in the frequency domain and, for a normal cyclic prefix ineach OFDM symbol, 7 consecutive OFDM symbols in the time domain, or 84resource elements. For an extended cyclic prefix, a resource blockcontains 6 consecutive OFDM symbols in the time domain and has 72resource elements. Some of the resource elements, as indicated as R 302,304, include downlink reference signals (DL-RS). The DL-RS includeCell-specific RS (CRS) (also sometimes called common RS) 302 andUE-specific RS (UE-RS) 304. UE-RS 304 are transmitted only on theresource blocks upon which the corresponding physical downlink sharedchannel (PDSCH) is mapped. The number of bits carried by each resourceelement depends on the modulation scheme. Thus, the more resource blocksthat a UE receives and the higher the modulation scheme, the higher thedata rate for the UE.

FIG. 4 is a diagram 400 illustrating an example of an uplink framestructure in LTE. The available resource blocks for the uplink may bepartitioned into a data section and a control section. The controlsection may be formed at the two edges of the system bandwidth and mayhave a configurable size. The resource blocks in the control section maybe assigned to UEs for transmission of control information. The datasection may include all resource blocks not included in the controlsection. The uplink frame structure results in the data sectionincluding contiguous subcarriers, which may allow a single UE to beassigned all of the contiguous subcarriers in the data section.

A UE may be assigned resource blocks 410 a, 410 b in the control sectionto transmit control information to an eNodeB. The UE may also beassigned resource blocks 420 a, 420 b in the data section to transmitdata to the eNodeB. The UE may transmit control information in aphysical uplink control channel (PUCCH) on the assigned resource blocksin the control section. The UE may transmit only data or both data andcontrol information in a physical uplink shared channel (PUSCH) on theassigned resource blocks in the data section. An uplink transmission mayspan both slots of a subframe and may hop across frequency.

A set of resource blocks may be used to perform initial system accessand achieve uplink synchronization in a physical random access channel(PRACH) 430. The PRACH 430 carries a random sequence and cannot carryany uplink data/signaling. Each random access preamble occupies abandwidth corresponding to six consecutive resource blocks. The startingfrequency is specified by the network. That is, the transmission of therandom access preamble is restricted to certain time and frequencyresources. There is no frequency hopping for the PRACH. The PRACHattempt is carried in a single subframe (1 ms) or in a sequence of fewcontiguous subframes and a UE can make only a single PRACH attempt perframe (10 ms).

FIG. 5 is a diagram 500 illustrating an example of a radio protocolarchitecture for the user and control planes in LTE. The radio protocolarchitecture for the UE and the eNodeB is shown with three layers: Layer1, Layer 2, and Layer 3. Layer 1 (L1 layer) is the lowest layer andimplements various physical layer signal processing functions. The L1layer will be referred to herein as the physical layer 506. Layer 2 (L2layer) 508 is above the physical layer 506 and is responsible for thelink between the UE and eNodeB over the physical layer 506.

In the user plane, the L2 layer 508 includes a media access control(MAC) sublayer 510, a radio link control (RLC) sublayer 512, and apacket data convergence protocol (PDCP) 514 sublayer, which areterminated at the eNodeB on the network side. Although not shown, the UEmay have several upper layers above the L2 layer 508 including a networklayer (e.g., IP layer) that is terminated at the PDN gateway 118 on thenetwork side, and an application layer that is terminated at the otherend of the connection (e.g., far end UE, server, etc.).

The PDCP sublayer 514 provides multiplexing between different radiobearers and logical channels. The PDCP sublayer 514 also provides headercompression for upper layer data packets to reduce radio transmissionoverhead, security by ciphering the data packets, and handover supportfor UEs between eNodeBs. The RLC sublayer 512 provides segmentation andreassembly of upper layer data packets, retransmission of lost datapackets, and reordering of data packets to compensate for out-of-orderreception due to hybrid automatic repeat request (HARQ). The MACsublayer 510 provides multiplexing between logical and transportchannels. The MAC sublayer 510 is also responsible for allocating thevarious radio resources (e.g., resource blocks) in one cell among theUEs. The MAC sublayer 510 is also responsible for HARQ operations.

In the control plane, the radio protocol architecture for the UE andeNodeB is substantially the same for the physical layer 506 and the L2layer 508 with the exception that there is no header compressionfunction for the control plane. The control plane also includes a radioresource control (RRC) sublayer 516 in Layer 3 (L3 layer). The RRCsublayer 516 is responsible for obtaining radio resources (i.e., radiobearers) and for configuring the lower layers using RRC signalingbetween the eNodeB and the UE.

FIG. 6 is a block diagram of an eNodeB 610 in communication with a UE650 in an access network. In the downlink, upper layer packets from thecore network are provided to a controller/processor 620. Thecontroller/processor 620 implements the functionality of the L2 layer.In the downlink, the controller/processor 620 provides headercompression, ciphering, packet segmentation and reordering, multiplexingbetween logical and transport channels, and radio resource allocationsto the UE 650 based on various priority metrics. Thecontroller/processor 620 is also responsible for HARQ operations,retransmission of lost packets, and signaling to the UE 650.

The TX processor 616 implements various signal processing functions forthe L1 layer (i.e., physical layer). The signal processing functionsincludes coding and interleaving to facilitate forward error correction(FEC) at the UE 650 and mapping to signal constellations based onvarious modulation schemes (e.g., binary phase-shift keying (BPSK),quadrature phase-shift keying (QPSK), M-phase-shift keying (M-PSK),M-quadrature amplitude modulation (M-QAM)). The coded and modulatedsymbols are then split into parallel streams. Each stream is then mappedto an OFDM subcarrier, multiplexed with a reference signal (e.g., pilot)in the time and/or frequency domain, and then combined together using anInverse Fast Fourier Transform (IFFT) to produce a physical channelcarrying a time domain OFDM symbol stream. The OFDM stream is spatiallyprecoded to produce multiple spatial streams. Channel estimates from achannel estimator 632 may be used to determine the coding and modulationscheme, as well as for spatial processing. The channel estimate may bederived from a reference signal and/or channel condition feedbacktransmitted by the UE 650. Each spatial stream is then provided to adifferent antenna 612 (612-1, 612-N) via separate transmitters 614 TX(614-1, . . . , 614-N). Each of the transmitters 614 TX modulates an RFcarrier with a respective spatial stream for transmission.

At the UE 650, a first receiver 654-1 RX-1 receives a signal through afirst antenna 652-1, and a second receiver 654-2 RX-2 receives a signalthrough a second antenna 652-2. The first receiver 654-1 RX-1 recoversinformation modulated onto an RF carrier and provides the information toa first receiver (RX-1) processor 660-1. The second receiver 654-2 RX-2also recovers information modulated onto an RF carrier and provides theinformation to a second receiver (RX-2) processor 660-2. The first RX-1processor 660-1 and the second RX-2 processor 660-2 implement varioussignal processing functions of the L1 layer. The first RX-1 processor660-1 and the second RX-2 processor 660-2 perform spatial processing onthe information to recover any spatial streams destined for the UE 650.If multiple spatial streams are destined for the UE 650, they may becombined by the first RX-1 processor 660-1 and the second RX-2 processor660-2 into single OFDM symbol streams. The RX-1 processor 660-1 and thesecond RX-2 processor 660-2 may then convert the OFDM symbol streamsfrom the time-domain to the frequency domain using a Fast FourierTransform (FFT). The frequency domain signal comprises a separate OFDMsymbol stream for each subcarrier of the OFDM signal. The symbols oneach subcarrier, and the reference signal, are recovered and demodulatedby determining the most likely signal constellation points transmittedby the eNodeB 610. These soft decisions may be based on channelestimates computed by the channel estimator 664. The soft decisions arethen decoded and de-interleaved to recover the data and control signalsthat were originally transmitted by the eNodeB 610 on the physicalchannel. The data and control signals are then provided to thecontroller/processor 680.

The controller/processor 680 implements the L2 layer. Thecontroller/processor can be associated with a memory 682 that storesprogram codes and data. The memory 682 may be referred to as acomputer-readable medium. In the uplink, the controller/processor 680provides de-multiplexing between transport and logical channels, packetreassembly, deciphering, header decompression, control signal processingto recover upper layer packets from the core network. The upper layerpackets are then provided to a data sink 662, which represents all theprotocol layers above the L2 layer. Various control signals may also beprovided to the data sink 662 for L3 processing. Thecontroller/processor 680 is also responsible for error detection usingan acknowledgement (ACK) and/or negative acknowledgement (NACK) protocolto support HARQ operations.

In the uplink, a data source 672 is used to provide upper layer packetsto the controller/processor 680. The data source 672 represents allprotocol layers above the L2 layer. Similar to the functionalitydescribed in connection with the downlink transmission by the eNodeB610, the controller/processor 680 implements the L2 layer for the userplane and the control plane by providing header compression, ciphering,packet segmentation and reordering, and multiplexing between logical andtransport channels based on radio resource allocations by the eNodeB610. The controller/processor 680 is also responsible for HARQoperations, retransmission of lost packets, and signaling to the eNodeB610.

Channel estimates derived by a channel estimator 664 from a referencesignal or feedback transmitted by the eNodeB 610 may be used by the TXprocessor 670 to select the appropriate coding and modulation schemes,and to facilitate spatial processing. The spatial streams generated bythe TX processor 670 are provided to an antenna 656 via a transmitter658 TX. The transmitter 658 TX modulates an RF carrier with a respectivespatial stream for transmission.

The uplink transmission is processed at the eNodeB 610 in a mannersimilar to that described in connection with the receiver function atthe UE 650. Each of the receivers 614 RX (614-1, . . . , 614-N) receivesa signal through its respective antenna 612 (612-1, . . . , 612-N). Eachof the receivers 614 RX recovers information modulated onto an RFcarrier and provides the information to one of the RX processors 630(630-1, . . . , 630-N). The RX processors 630 may implement the L1layer.

The controller/processor 620 implements the L2 layer. Thecontroller/processor 620 can be associated with a memory 622 that storesprogram codes and data. The memory 622 may be referred to as acomputer-readable medium. In the uplink, the controller/processor 620provides demultiplexing between transport and logical channels, packetreassembly, deciphering, header decompression, control signal processingto recover upper layer packets from the UE 650. Upper layer packets fromthe controller/processor 620 may be provided to the core network. Thecontroller/processor 620 is also responsible for error detection usingan ACK and/or NACK protocol to support HARQ operations

The controller/processor 620 and the controller/processor 680 may directthe operation at the eNodeB 610 and the UE 650, respectively. Thecontroller/processor 620 and/or other processors and modules at theeNodeB 610 may perform or direct the execution of various processes forthe techniques described herein. The controller/processor 680 and/orother processors and modules at the UE 650 may also perform or directthe execution of the functional blocks illustrated in use in the methodflow charts of FIGS. 7 and 8 and/or other processes for the techniquesdescribed involving a voice/data hybrid mode within the UE 650. In thisconfiguration, the UE 650 includes a first radio access technology (RAT)690-1 and a second RAT 690-2 that share a single receive path to providethe voice/data hybrid mode. The memory 622 and the memory 682 may storedata and program codes for the eNodeB 610 and the UE 650, respectively.

Voice/Data Hybrid Mode within a Radio Ue

One aspect of the present disclosure provides a UE that receives dataover a first radio access technology (RAT) and voice over a second radioaccess technology (RAT) while supporting a single receive path. In thisaspect of the disclosure, a first receive chain and a second receivechain of the single receive path are shared between a first radio accesstechnology (RAT) modem and a second RAT modem. In one configuration, thefirst RAT modem is an LTE modem and the second RAT is a 1× (CDMA2000)modem.

CDMA2000 includes but is not limited to single carrier radiotransmission technology (1×RTT), 1× evolution-data optimized (1×EV-DO),and other like mobile technology standards that use CDMA channel accessfor sending voice, data, and signaling data between mobile phones andcell sites. As described herein CDMA2000 may be referred to as 1×. Otherconfigurations of the first and second RAT modems are possible whileremaining within the scope of the appended claims and the inventiveaspects of the present disclosure. For example the first and second RATmodems could be for HSPA and GSM or any other network. The followingdescription is provided with respect to 1× and LTE for ease ofillustration.

Simultaneous voice and LTE (SVLTE) is the current de facto standard forvoice delivery when LTE is an overlay to a CDMA2000 (1×) network. InSVLTE communication, voice service is deployed as a 1× service that runsin parallel with LTE data services. As a result, a handset runs tworadios simultaneously to implement SVLTE communication. Several voicesolutions are available to C2K (CDMA2000) operators that are planning onreleasing a multimode LTE/C2K handset. These include options thatinvolve network support and/or upgrades including: (1) voice over IPover LTE (VoLTE) and (2) 1× Circuit Switched Fallback (1×CSFB); andoptions that specify reduced or no network support including: (1) dualreceiver 1×CSFB and (2) SVLTE.

The assumption behind options that do not involve network support isthat the device either supports dual receive paths or dual receive/dualtransmit paths. It should be noted that dual receive paths in an LTE UEimplies three receive chains for supporting MIMO (multiple inputmultiple output) operation in LTE. Dual receive paths enable a UE toindependently monitor LTE paging and 1× paging, as specified forsupporting dual receiver CSFB communication. Dual receive/dual transmitpaths enable a UE to support independent 1× and LTE operation, asspecified for supporting SVLTE communication.

One aspect of the present disclosure provides a UE that receives dataover LTE and voice over 1× while supporting a single receive path. Inthis aspect of the disclosure, a UE provides a voice/data hybrid mode inwhich a single receive path that includes a first receive chain and asecond receive chain is shared between a first radio access technology(RAT) modem and a second RAT modem. In one configuration, the singlereceive path implies two receive chains for supporting MIMO operation inLTE.

FIG. 7 illustrates a method 700 for a voice/data (e.g., 1×/LTE) hybridmode operation according to an aspect of the present disclosure. In oneaspect of the present disclosure, a primary (first) receive chain and adiversity (second) receive chain are shared between an LTE modem and a1× modem of a UE. For example, as shown in FIG. 6, the UE 650 includes afirst RAT 690-1 (e.g., an LTE modem) and a second RAT 690-2 (e.g., a 1×modem) that share a single receive path. In this configuration, a firstreceiver 654-1 RX-1 has a first antenna 652-1 and a second receiver654-2 RX-2 has a second antenna 652-2 that are shared between the firstRAT 690-1 and the second RAT 690-2 of the UE 650.

In one configuration, the sharing of the primary (e.g., the firstreceiver 654-1 RX-1, the first antenna 652-1, and the first RX-1processor 660-1) and diversity (second receiver 654-2 RX-2, the secondantenna 652-1, and the second RX-2 processor 660-2) receive chains ofthe UE 650 prohibits camping on both an LTE network and a 1× network. Asa result, 1× pages and LTE pages may collide during operation of the UE650. A tune-away from LTE to listen for 1× pages or perform other like1× activity is referred to as a “1× tune-away.” The 1× tune-away resultsfrom sharing of the primary and diversity receive chains to provide avoice/data hybrid mode. In this configuration, the first RAT 690-1 andthe second RAT 690-2 adaptively share the primary and diversity receivechains to enable reception of LTE data and 1× voice calls.

The 1× tune-away from LTE is performed in response to an LTE suspendrequest to listen for 1× pages or other like 1× activity. The 1×tune-away results from the received LTE suspend request. Conventionalapproaches tune-away from LTE in response to LTE suspend requestsregardless of the activity taking place on LTE, which may be referred toas “LTE activity.” In contrast to the conventional approach, a receivedLTE suspend request may or may not be performed depending on thepriority of the current LTE activity and a 1× tune-away activity.

One aspect of the disclosure supports a framework in which LTE suspendrequests are adaptively honored for 1× tune-away. For instance, becauseinterrupting the following LTE activities could lead to catastrophicconsequences on LTE, the UE may choose to ignore the LTE suspend requestand not honor the 1× tune-away if the UE is in the middle of apredetermined LTE activity including, but not limited to: (1) an LTEattach; (2) an inter-eNB/inter-RAT HO (radio access technologyhandover); (3) security procedures; (4) a TAU (tracking area update);and (5) device provisioning or software updates triggered by thenetwork. Repeated breaks may result in an inconsistent state between thenetwork and the UE. In addition, breaking away from LTE when thefollowing events are about to occur could lead to Global CertificationForum (GCF) test violations: (1) UE is in the middle of aRequest-Response messages in NAS/RRC (non-access stratum/radio resourcecontrol) specification; or (2) a timer at which the UE is expected toretry an activity is about to expire.

Referring again to FIG. 7, the method 700 for adaptively honoring LTEsuspend requests for 1× tune-away is described. In block 710, a firstradio access technology (RAT) activity is detected in response to areceived first RAT suspend request for a second RAT tune-away. Forexample, during operation of a UE 650, the UE 650 detects an LTEactivity in response to a received LTE suspend request for a 1×tune-away activity. In block 712, the UE adaptively performs the firstRAT suspend request according to a predetermined priority of thedetected first RAT activity and the second RAT tune-away activity. Inthis configuration, the first receive chain and the second receive chainare shared between the LTE modem and the 1× modem of the UE 650.

For example, the UE 650 adaptively performs the LTE suspend requestaccording to a predetermined priority of the detected LTE activity and a1× tune-away. A 1× tune-way for a mobile or UE terminated activity(e.g., incoming activity) may be awarded priority over the detected LTEactivity. Conversely, the detected LTE activity may be awarded priorityover a mobile or UE originated activity (e.g., an outgoing activity). Inthis configuration, the LTE suspend request is received to enable a 1×tune-away.

That is, the UE may distinguish between a LTE suspend request for amobile originated 1× activity versus a LTE suspend request for mobileterminated page reception. If the suspend request is for mobileoriginated activity, then the UE can take a longer time to respond tothe suspend request if it is in the middle of an important LTE activity.On the other hand, the UE will be more stringent about delaying asuspend request for a mobile terminated page reception.

This aspect of the disclosure adaptively honors LTE suspend requestsaccording to the importance of the LTE activity, such that predeterminedLTE activities take priority over a 1× tune-away. For example, delayinga mobile originated activity by a few seconds slightly degrades the userexperience. In this aspect of the disclosure, the LTE suspend requestindicates whether the request is for a mobile originated or a mobileterminated (MT) activity. For a mobile originated activity, delaying thehonoring of an LTE suspend request is more likely so that the LTEactivity may complete. Conversely, for mobile terminated activities, theLTE suspend request is delayed only for the higher priority LTEactivities.

One configuration of the voice/data hybrid mode enables a single receivechain in an LTE connected mode while performing 1× paging requests. Inparticular, rather than suspending LTE to enable performance of the 1×paging requests, the UE 650 may temporarily operate as a single outputdevice. That is, the UE 650 informs the network that it is temporarilyoperating as a single output device, such that the UE has access to asingle receive chain. As a result, the UE 650 operates at a reduced ratewithout completely shutting down LTE, while being able to perform the 1×paging requests. For example, during an LTE traffic mode, the UE 650reduces a rank to one (1), thereby allowing an LTE call (with a singlereceive chain) simultaneous with 1× page monitoring (using the otherreceive chain).

FIG. 8 illustrates a method 800 for voice/data hybrid mode within a UE650 according to an aspect of the present disclosure. This aspect of thedisclosure modifies the behavior of 1× out-of-service (OoS) behavior byexecuting full scans repeatedly, while accounting for back-offs. Thecurrent behavior is to scan for available 1× systems for 15 minutescontinuously with a subsequent telescopic backoff for scans. Similarly,the system selection scans prevent situations where the LTE systemacquisition (during RLF (radio link failure), OoS scan, etc.) does notinterfere with a 1× paging wakeup.

At block 810, a first receive chain and a second receive chain areshared between a first RAT modem and a second RAT modem of a UE. Atblock 812, a first radio access technology (RAT) scan is adaptivelyperformed between a second radio access technology (RAT) activity inresponse to an out of service (OoS) event. In this aspect of thedisclosure, 1× scans are adaptively performed in between LTE activitywhen 1× is out of coverage. Similarly, LTE system acquisition isperformed in an adaptive manner for managing interference with 1× pagingwakeup events or other like 1× tune-away activity when LTE is out ofcoverage.

An issue that arises due to the receive path limitation of the UE 650when providing a voice/data hybrid mode is the complexity in dealingwith the cases in which 1× and LTE page cycles overlap. That is, 1×paging occasions can collide with LTE paging occasions. Preferred cyclenegotiation may be used to overcome such problems when the LTE and 1×networks are synchronized. Otherwise, if the arrival of a suspendtrigger to read a 1× page can be anticipated, the UE 650, either priorto receiving the suspend trigger, or after receiving the trigger butprior to suspension, may signal to the network that it desires toincrease the LTE paging cycle duration. Doing so decreases theprobability of collision of multiple LTE page durations with theduration of LTE suspension.

The UE 650 could also use the network signaling to either request anincrease in the paging cycle, or use the network signaling to explicitlyrequest a precise paging cycle value. For example, upon determining thatsuspension for a 1× page reception has ended, or is not likely to arriveagain soon, the UE 650 may signal to the network that it desires toreduce its paging cycle duration to enable receipt of pages in anexpedited fashion. In other words, if a collision is expected, the UE650 may request that the LTE network change a duration of the pagingcycle.

In operation, an LTE suspend to read a 1× page may be overruled by ahigher priority procedure on LTE. As a result, a page would be missed,in which case the network will re-page the UE. The paging cyclemodification is performed to at least avoid a miss of the re-page fromthe network. In this configuration, after a suspend to read a 1× page isoverruled, it should be ensured that on the next paging occasion,reading of the 1× page takes absolute priority. In other words, at adevice level, to ensure the probability of missing two consecutive pagesis low, such that the impact of collisions is reduced, in thisconfiguration, the priority is reversed so that two consecutive pagingrequests are not missed.

The voice/data hybrid mode may enable a connection to both an LTEnetwork and a CDMA2000 network, while maintaining registration andoverhead information on both types of networks concurrently. The UE 650,however, does not have a signaling mechanism for communicating with theLTE network to indicate the honoring of an LTE suspension request totune-away for responding to a 1× paging request.

An eNB scheduler may implement mechanisms to throttle back downlinkassignments if a UE goes into a temporary outage when responding to a 1×paging request. During the outage, the eNB will not read the uplink LTEcontrol channels carrying channel quality indicator (CQI) and/or ACK/NAK(acknowledgement/negative acknowledgement) information. For example, thescheduler may have a control loop that applies an offset to the CQIbased scheduling determined by the history of ACK/NACKs received. If anumber of subsequent NACKs are received (as would be the case duringsuspend), the scheduler would apply a negative offset (delta) to theCQI, and schedule the UE with smaller packet sizes than suggested by theUE reported CQI.

To remedy this, the UE could have a mechanism that compares thescheduled packet size with the expected packet size, in accordance withthe reported CQI. If the actual packet size is much smaller thanexpected, the UE can apply a corresponding positive offset to thereported CQI. That is, the UE reports a CQI and the eNB schedules a datarate based on the CQI. Honoring of LTE suspend requests causes a largenumber of packet drops. Dropping the scheduling rate due to reduced CQIreporting also leads to packet loss. Therefore, the eNB gradually dropsthe data rate based on the dropped/lost packets. After the tune-away,the data rate is gradually increased, which leads to an insufficientdata rate. In this aspect of the disclosure, after the return from thetune-away is complete and the data rate is not consistent with the CQIs,then the mobile device reports a CQI that is higher than what isactually experienced (e.g., CQI(×)+delta). As a result, the ramp-up ofthe data rate at the network occurs more quickly.

Further enhancements may include the application of a positive offsettemporarily after the resume. In addition, the UE 650 may stop applyingthe offset as soon as a NACK is triggered. The UE 650 may also graduallyramp up the positive offset on ACK as well as gradually ramp thepositive offset down on NACK. Further, the UE 650 may start ramping downthe CQI leading up to the suspend.

In another aspect of the disclosure, when measurement schedulingcollides with 1× operation, the measurement gap is either not scheduledor is aborted. Also, the measurement report is not reported to thenetwork. Reporting of incorrect measurement reports to the network isavoided. That is, the periodic measurement may be incorrect because theUE may be tuned away for 1× tune-away activity.

In a further aspect of the disclosure, the UE ignores a RLC (radio linkcontroller) reset in the uplink (UL) if the RLC is due to a tune-away. Ahigher priority may be awarded to LTE when approaching a maximum numberof RLC resets. That is, if the maximum number of RLC resets is near,then the tune-away will not occur. In this aspect of the disclosure, RLCresets that are due to 1× tune-away are ignored so that the uplinkconnection is not released. That is, a 1× tune-away is not performedonce the UE begins approaching the maximum RLC reset amount to avoid aloss of the LTE connection. Flow control applications may also beadjusted to accommodate for the 1× tune-away (e.g., for voice calls).

In another configuration, the voice/data hybrid mode supports QoS(quality of service) flow maintenance. Real-time activities that are QoScentric may result in disregarding a predetermined number of 1×tune-aways. If the UE detects a QoS call on LTE (e.g., a Skypecall/VoLTE call), an option is provided to disable the 1× tune-away. IfUE has voice through some other means with a separate RF chain (e.g.,WiFi), the UE may stop monitoring 1×. If the UE has data through someother means with a separate RF chain (e.g., WiFi), the UE can suspendLTE operation.

In another configuration, the voice/data hybrid mode is adjusted toaccommodate a short message service. For example, mobile originatedshort message service (SMS) messages may be re-routed over 1× during thevoice call, and over IMS (i.e., SMS over a data network) when the UE isnot on a 1× voice call. During LTE suspension, it is anticipated thatthe UE will remain on 1× for a brief period, unless the UE is involvedin a 1× circuit switched call. While the UE is tuned to 1×, and LTE issuspended, the UE maintains the IMS registration context over LTE. Inthis configuration, the UE uses IMS as the default SMS transport andattempts sending SMS messages over IMS. Nevertheless, when the mobileoriginated SMS message attempt over IMS fails after a stipulated amountof retries, the UE should check to see if the LTE stack is currently insuspension. If this is true, the UE should attempt to send the SMSmessages over 1×, while continuing to maintain the IMS context over LTE.

The UE may support domain availability notification to help the networkstart routing SMS messages over 1× if reducing SMS interruption isimportant. Movement of the SMS domain over 1× may also result in havingto perform IMS re-registration upon returning to LTE. This is designedbased on inputs from the operator on their SMS sequential retry logic.In this configuration, when the UE tunes-away to LTE to receive pages,the SMS domain is maintained over IMS for a certain duration to preventa change in the SMS domain during short outages.

In another aspect of the disclosure, applications are throttled duringthe transitions from LTE for 1× monitoring to enable the voice/datahybrid mode. Throttling of applications may cause buffer overflows atthe application/HLOS (high level operating system). Applicationthrottling may prevent technology change notifications from being postedto the application when the UE has transitioned to 1× for periodicmonitoring and during voice calls. Application flow control may beperformed to avoid indicating to the applications that a 1× tune-away isbeing performed for ensuring that an IP context is saved. Otherwise, theIP context is torn down by the application if communication of the 1×tune-away is not blocked from the application.

In a further aspect of the disclosure, the UE predicts when asuspend/tune-away is going to happen. During the predictedsuspend/tune-away, the UE does not engage in activities on the LTE sidethat cannot be completed prior to the predicted suspend/tune-away. Basedon the UE knowledge of a 1× tune-away, the 1× tune-away is rescheduledto avoid overlap with an LTE activity (e.g., an LTE tracking areaupdate) that cannot be completed if the 1× tune-away is performed. The1× tune-way is rescheduled to reduce the probability of overlap. Inaddition, the receive window for a TCP (transmission control protocol)may be collapsed during active data transitions to prevent TCP back-offsand unnecessary congestions in the network. For example, the transmitrate may be reduced or transmission may be halted during the 1×tune-away.

The voice/data hybrid mode may occasionally miss a 1× paging slot. Inthe event that a page is missed, this configuration relies on theretries from the 1× side. As indicated above, certain high priority LTEactivities are awarded priority over 1× tune-aways. In thisconfiguration, after a suspend to read a 1× page is overruled by ahigher priority LTE activity, it should be ensured that on the nextpaging occasion, reading of the 1× page takes priority. To ensure thatthe probability of missing two consecutive pages is low, in thisconfiguration, the priority is reversed (e.g., the 1× tune-away trumpsthe LTE priority) so that two consecutive paging requests are notmissed.

FIG. 9 is a diagram illustrating an example of a hardware implementationfor an apparatus 900 employing a voice data hybrid mode according to oneaspect of the present disclosure. The voice/data hybrid mode system 914may be implemented with a bus architecture, represented generally by abus 924. The bus 924 may include any number of interconnecting buses andbridges depending on the specific application of the voice/data hybridmode system 914 and the overall design constraints. The bus 924 linkstogether various circuits including one or more processors and/orhardware modules, represented by a processor 926, a detecting module902, an adaptive performing module 904, a sharing module 906, and acomputer-readable medium 928. The bus 924 may also link various othercircuits such as timing sources, peripherals, voltage regulators, andpower management circuits, which are well known in the art, andtherefore, will not be described any further.

The apparatus includes the voice/data hybrid mode system 914 coupled toa transceiver 922. The transceiver 922 is coupled to one or moreantennas 920. The transceiver 922 provides a means for communicatingwith various other apparatus over a transmission medium. The voice/datahybrid mode system 914 includes the processor 926 coupled to thecomputer-readable medium 928. The processor 926 is responsible forgeneral processing, including the execution of software stored on thecomputer-readable medium 928. The software, when executed by theprocessor 926, causes the voice/data hybrid mode system 914 to performthe various functions described supra for any particular apparatus. Thecomputer-readable medium 928 may also be used for storing data that ismanipulated by the processor 926 when executing software.

The voice/data hybrid mode system 914 further includes the detectingmodule 902 for detecting a first radio access technology (RAT) activityin response to a received first RAT suspend request for a second RATtune-away. The system 914 also includes the adaptive performing module904 for adaptively performing the first RAT suspend request according toa predetermined priority of the detected first RAT activity and a secondRAT tune-away activity. The system 914 also has the sharing module 906for sharing a first receive chain and a second receive chain between afirst RAT modem and a second RAT modem. The detecting module 902, theadaptive performing module 904, and the sharing module may be softwaremodules running in the processor 926, resident/stored in thecomputer-readable medium 928, one or more hardware modules coupled tothe processor 926, or some combination thereof. The voice/data hybridmode system 914 may be a component of the UE 650.

In one configuration, the apparatus 900 for wireless communicationincludes means for detecting and means for adaptively performing. Themeans may be the detecting module 902, the adaptive performing module904 and/or the voice/data hybrid mode system 914 of the apparatus 900configured to perform the functions recited by the detecting means andthe adaptive performing means. In one aspect of the present disclosure,the detecting means may be the controller/processor 680 and/or memory682 configured to perform the functions recited by the detecting means.In this aspect of the disclosure, the adaptive performing means may bethe controller/processor 680 and/or memory 682 configured to perform thefunctions recited by the adaptive performing means. In this aspect ofthe disclosure, the sharing means may be the controller/processor 680and/or memory 682, the first RX-1 processors 660-1, the second RX-2processor 660-2, the transmit TX processor 670, and/or the firstreceiver 654-1 RX-1, and/or the second receiver 654-2 RX-2 configured toperform the functions recited by the sharing means. In another aspect,the aforementioned means may be any module or any apparatus configuredto perform the functions recited by the aforementioned means.

The examples above describe aspects implemented in LTE and 1× systems.However, the scope of the disclosure is not so limited. Various aspectsmay be adapted for use with other communication systems, such as thosethat employ any of a variety of communication protocols including, butnot limited to, CDMA systems, TDMA systems, FDMA systems, and OFDMAsystems.

Those of skill would further appreciate that the various illustrativelogical blocks, modules, circuits, and algorithm steps described inconnection with the disclosure herein may be implemented as electronichardware, computer software, or combinations of both. To clearlyillustrate this interchangeability of hardware and software, variousillustrative components, blocks, modules, circuits, and steps have beendescribed above generally in terms of their functionality. Whether suchfunctionality is implemented as hardware or software depends upon theparticular application and design constraints imposed on the overallsystem. Skilled artisans may implement the described functionality invarying ways for each particular application, but such implementationdecisions should not be interpreted as causing a departure from thescope of the present disclosure.

The various illustrative logical blocks, modules, and circuits describedin connection with the disclosure herein may be implemented or performedwith a general-purpose processor, a digital signal processor (DSP), anapplication specific integrated circuit (ASIC), a field programmablegate array (FPGA) or other programmable logic device, discrete gate ortransistor logic, discrete hardware components, or any combinationthereof designed to perform the functions described herein. Ageneral-purpose processor may be a microprocessor, but in thealternative, the processor may be any conventional processor,controller, microcontroller, or state machine. A processor may also beimplemented as a combination of computing devices, e.g., a combinationof a DSP and a microprocessor, a plurality of microprocessors, one ormore microprocessors in conjunction with a DSP core, or any other suchconfiguration.

The steps of a method or algorithm described in connection with thedisclosure herein may be embodied directly in hardware, in a softwaremodule executed by a processor, or in a combination of the two. Asoftware module may reside in RAM memory, flash memory, ROM memory,EPROM memory, EEPROM memory, registers, hard disk, a removable disk, aCD-ROM, or any other form of storage medium known in the art. Anexemplary storage medium is coupled to the processor such that theprocessor can read information from, and write information to, thestorage medium. In the alternative, the storage medium may be integralto the processor. The processor and the storage medium may reside in anASIC. The ASIC may reside in a user terminal. In the alternative, theprocessor and the storage medium may reside as discrete components in auser terminal.

In one or more exemplary designs, the functions described may beimplemented in hardware, software, firmware, or any combination thereof.If implemented in software, the functions may be stored on ortransmitted over as one or more instructions or code on acomputer-readable medium. Computer-readable media includes both computerstorage media and communication media including any medium thatfacilitates transfer of a computer program from one place to another. Astorage media may be any available media that can be accessed by ageneral purpose or special purpose computer. By way of example, and notlimitation, such computer-readable media can comprise RAM, ROM, EEPROM,CD-ROM or other optical disk storage, magnetic disk storage or othermagnetic storage devices, or any other medium that can be used to carryor store desired program code means in the form of instructions or datastructures and that can be accessed by a general-purpose orspecial-purpose computer, or a general-purpose or special-purposeprocessor. Also, any connection is properly termed a computer-readablemedium. For example, if the software is transmitted from a website,server, or other remote source using a coaxial cable, fiber optic cable,twisted pair, digital subscriber line (DSL), or wireless technologiessuch as infrared, radio, and microwave, then the coaxial cable, fiberoptic cable, twisted pair, DSL, or wireless technologies such asinfrared, radio, and microwave are included in the definition of medium.Disk and disc, as used herein, includes compact disc (CD), laser disc,optical disc, digital versatile disc (DVD), floppy disk and Blu-ray discwhere disks usually reproduce data magnetically, while discs reproducedata optically with lasers. Combinations of the above should also beincluded within the scope of computer-readable media.

The previous description of the disclosure is provided to enable anyperson skilled in the art to make or use the disclosure. Variousmodifications to the disclosure will be readily apparent to thoseskilled in the art, and the generic principles defined herein may beapplied to other variations without departing from the spirit or scopeof the disclosure. Thus, the disclosure is not intended to be limited tothe examples and designs described herein but is to be accorded thewidest scope consistent with the principles and novel features disclosedherein.

What is claimed is:
 1. A method of wireless communication in a userequipment (UE), comprising: adaptively performing a first radio accesstechnology (RAT) scan between a second radio access technology (RAT)activity in response to an out of service (OoS) event, in which areceive chain is shared between a first RAT modem and a second RAT modemof the UE.
 2. The method of claim 1, further comprising adaptivelyperforming a second RAT system acquisition to reduce interference with afirst RAT tune-away.
 3. The method of claim 1, in which a first RATcomprises CDMA2000 and a second RAT comprises long term evolution (LTE).4. An apparatus configured for wireless communication within a userequipment (UE), the apparatus comprising: a memory; and at least oneprocessor coupled to the memory, the at least one processor beingconfigured: to adaptively perform a first radio access technology (RAT)scan between a second radio access technology (RAT) activity in responseto an out of service (OoS) event, in which a receive chain is sharedbetween a first RAT modem and a second RAT modem of the UE.
 5. Theapparatus of claim 4, in which the processor is further configured toadaptively perform a second RAT system acquisition to reduceinterference with a first RAT tune-away.
 6. The apparatus of claim 4, inwhich a first RAT comprises CDMA2000 and a second RAT comprises longterm evolution (LTE).
 7. A computer program product configured forwireless communication within a user equipment (UE), the computerprogram product comprising: a computer-readable medium havingnon-transitory program code recorded thereon, the program codecomprising: program code to adaptively perform a first radio accesstechnology (RAT) scan between a second radio access technology (RAT)activity in response to an out of service (OoS) event, in which areceive chain is shared between a first RAT modem and a second RAT modemof the UE.
 8. An apparatus for wireless communication within a userequipment (UE), comprising: means for adaptively performing a firstradio access technology (RAT) scan between a second radio accesstechnology (RAT) activity in response to an out of service (OoS) event,in which a receive chain is shared between a first RAT modem and asecond RAT modem of the UE.